Introduction

This bulletin describes three typical prairie communities: wet, mesic, and dry, and the plants found in these communities. Characteristics of each community are provided along with typical plants found in each site. This information should be useful to professional designers, teachers, landscape architects as well as amateur gardeners who have an interest in native plants and their landscape use.

Although the extensive table "Characteristics of Prairie Plants" lists 158 grasses and forbs, it is not offered as a comprehensive or exhaustive compilation of all native plants found in the area. However, an effort has been made to cover the more significant species occurring across the North Central region of the United States.

People are not always aware of protected and/or rare species. Each state has its own regulations as well as lists of threatened and endangered plants. Some states may require licensing or registration with the Department of Natural Resources (DNR) or other agency for collection and/or propagation of native plants. The by-word of all who are interested in native plants should be "Check before you collect." Check with your local county extension educator, the DNR, the Department of Agriculture, private landowners or the appropriate state agency if public lands are involved. In all cases, respect for the environment and other people's property is important.

Planting and maintenance of a prairie is beyond the scope of this publication. Consult the reference list for further information, and for references on botanical names and native plant organizations and horticultural societies.

Prairies in the United States

Prior to European settlement, vast grasslands or prairies existed throughout the central United States (Map 1). Today, very little of the original prairie exists due to commercial agriculture, development of communities, towns, roads, etc. Some estimates are that the shortgrass prairie and the mixed-grass prairie cover about 1/5 and 1/4, respectively, of the areas they once did. Of the tallgrass prairie, only about 1% remains in the United States today. These three grassland communities are based on rainfall. The higher annual precipitation in the east resulted in the tallgrass prairie and the decreased moisture westward resulted in shortgrass.

Within the major types of prairies (short, mixed, and tallgrass) exist communities of plants that thrive on specific sites. Three of the most common sites-wet, mesic, and dry-are discussed in this bulletin. Species composition of these three habitats changes as one goes from east (tallgrass) to west (shortgrass). A wet habitat in the tallgrass prairie is floristically quite different from a wet habitat in the shortgrass prairie. This publication generally applies to the tallgrass and mixed-grass regions. Many plants are quite restricted in their habitat preferences and may be limited to one habitat. for example, Aster simplex, panicled aster, prefers only wet sites, while other species, like Schizachyrium scoparium, little bluestem, and Oenothera pilosella, prairie sundrops, are more tolerant and may occur in all three communities.

Major grassland types of the U.S. and adjacent Canada and Mexico

Plants of wet prairies

The wet prairie plant community develops wherever the water table is high. Areas that are flooded or saturated by groundwater for more than a few days during a normal year are typical of wet prairies. Here the soil is waterlogged within the plant root zone for extended periods of time during the growing season. Local wet prairies develop in depressions where runoff accumulates or where the water table is close to the surface. The soil of wet prairie consists of silt and clay loam with high organic matter and nutrients. Wet prairie soils are poorly drained and are typically dominated by grasses with sedges an important component of the community. Forbs or wildflowers are abundant but usually fewer forb species occur in wet prairies than in mesic prairies. Plants found growing in this environment include:

Plants of dry prairies

Purple Prairie Clover Dalea purpureum

Big Bluestem Andropogon gerardi

Many dry prairies in the eastern grasslands are often found on steep hillsides or rocky areas that are not economically feasible to develop. Moving westward, dry prairies are more common in general due to the lower rainfall, between 10 and 20 inches per year. These dry prairie communities typically have a shallow soil profile, with a thin layer of organic matter and sandy, well-drained soil with low water-holding capacity. In western areas of the shortgrass prairie, evapotranspiration exceeds precipitation and can cause salts to accumulate in a hard layer three to six feet below the surface. This hardpan of limestone-like calcium carbonate causes the soil to be more alkaline and may be a distinguishing characteristic of the dry prairie community in the shortgrass prairie. This condition is rarely found in the tallgrass prairie, even in dry sites because the rainfall is adequate. Species composition varies in the dry prairie, depending on the soil, geography, topography, and climate. Typical plants found growing in the dry prairie community are:

Plants of mesic prairies

Indian Grass Sorghastrum nutans

Pasque Flower Pulsatilla patens

The mesic (from the Greek meso or middle, meaning neither wet nor dry) prairie community occurs in fairly level outwash deposits, gently rolling hills, or ground moraine. In some areas loess deposits (the fine wind-deposited material) overlie glacial till. Mesic prairies have lighter soil, receive or retain less water, and have more surface drainage than wet prairies. Most are found on loam and sandy loam soils. Rainwater soaks in but doesn't collect from the surrounding area. Mesic prairies may closely resemble dry communities, but grasses grow more vigorously and there are more flower species. These are ideal growing conditions for native legumes, which enrich the soil with nitrogen for other prairie species. Disturbance by fire, mowing, or grazing is necessary to prevent invasion by brush and trees. Common plants in this type of community include:

Characteristics of prairie plants

Key for table

Competitiveness: 1= aggressive, can compete with weedy and exotic species, easiest to establish; 2 = intermediate, not as competitive with weedy and exotic plants, slower to establish; 3 = competition sensitive, will not compete and declines or dies with weedy species and exotics.

Old fields, disturbed sites: Native prairie plants that can be found growing on extensively disturbed sites. These species can be tough enough to survive grazing, mowing, plowing, spraying, or some other land management practices.

Plants restricted to virgin prairies: Prairie plants found growing on virgin (not plowed or disturbed) prairie remnants. Most of these plants will not tolerate any kind of disturbance such as plowing, heavy grazing, or mowing.

Plants established by seeds or plants: Some prairie plants can be established by seeds (S) or (P) or both (S/P). Recommendations are based on the difficulty of germination, survival rate, growth rate, and what is currently available through nurseries. Native plants should be nursery-propagated and purchased through licensed nurseries to support the conservation of native species.

Comp.

Old fields

Virgin prairies

Establish.

Color

Height

Habitat

Period of bloom

Comments

Agastache foeniculumFragrant Hyssop

1

Yes

No

S/P

Purple

1-3'

Mesic

July-Aug.

Attractive dense, purple spiked flowers, aromatic flowers and leaves.

Agoseris glaucaPrairie Dandelion

3

No

Yes

P

Yellow

6-12"

Dry

June

Dandelion-like flowers. Rare in some areas.

Agropyron smithiiWestern Wheat Grass

2

No

No

S/P

-

16-24"

Dry

July

Most of growth occurs in spring and fall.

Allium canadenseWild Garlic

3

No

Yes

S/P

Pinkish

6-12"

Mesic-dry

May-June

Can't stand heavy grass competition. Needs small companions.

Allium cernuumNodding Onion

2

No

Yes

S/P

Pinkish

12-16"

Mesic-dry

July-Aug.

Can't stand heavy grass competition. Needs small companions.

Allium stellatumPrairie Onion

3

No

Yes

S/P

Pinkish

12-16"

Mesic-dry

July-Aug.

Can't stand heavy grass competition. Needs small companions.

Comp.

Old fields

Virgin prairies

Establish.

Color

Height

Habitat

Period of bloom

Comments

Amorpha canescensLead Plant

2

No

Yes

S/P

Purple

1-3'

Dry-mesic

June-July

A very showy woody shrub, grows slowy. A native legume.

Andropogon gerardiBig Bluestem

1

Yes

No

S/P

-

2-6'

Mesic-dry

Aug.-Sept.

A warm season grass, forms a solid sod, very aggressive on moist sites.

Anemone canadensisCanada Mayflower

1

No

No

P

White

12-18"

Mesic-wet

May-July

Found growing in colonies.

Anemone carolinianaCaroliana Anemone

3

No

Yes

P

White to Violet

8-15"

Dry

Apr.-May

Showy, needs small companions, sensitive to early spring fires.

Anemone cylindricaThimble Flower

2

No

No

S/P

White

12-16"

Dry-mesic

June-July

Seedheads are interesting, needs small companions.

Antennaria neglectaPussy toes

1

Yes

No

P

White

4-12"

Dry-mesic

May-June

Forms solid patches.

Comp.

Old fields

Virgin prairies

Establish.

Color

Height

Habitat

Period of bloom

Comments

Apocynum androsaemifoliumSpreading Dog bane

3

Yes

No

P

Pink

1-3'

Mesic

June-July

Small, aromatic flowers. Has milky juice like milkweed

Apocynum cannabinumIndian Hemp

3

No

No

P

Green-white

1-3'

Mesic-dry

June-Aug.

Small flowers. Has milky juice like milkweed

Aquilegia canadensisWild Columbine

2

Yes

No

S/P

Red-yellow

1-2'

Mesic

June-July

Self seeds readily. A species found in woods or prairies, very attractive.

Other prairie plant communities

Several other prairie plant communities are found in the Midwest, constituting a small fraction of the total vegetation that exists today. They contain the same herbaceous plant species found in the wet, mesic, and dry prairie communities, but in different proportions.

Oak Savanna

Oak savannas were a common ecotype between the eastern deciduous forest and the tallgrass prairie. These were park-like groves of oak, often bur oak, Quercus macrocarpa, and mesic prairie grasslands. Today most savannas have been destroyed, although some groves of trees still exist in pastures or in suburban housing developments. Fire was a significant factor in influencing the position and extent of this community. Some public land surveys of Minnesota indicate that rather than a park-like grove, this community may have been more brushland with small groves of trees intermixed with open prairie.

Fens

Fen is a geologic term used to describe low, swampy, boggy areas, but the word also describes the soil/plant relationship. Fens are wet prairie communities found on hillsides, fed by internal springs, associated with either extinct or existing glacial lakes of a dolomitic limestone source. Water and soil conditions tend to vary slightly from site to site, but they generally tend to be high in magnesium sulfates, magnesium and calcium bicarbonates. Sedges and grasses are the dominant plants found in fens.

Aspen Parkland

The aspen parkland plant communities are found in the far north of the Midwest, a transition area between the coniferous forest to the northeast and the prairie communities of the west. Ancient beach ridges hold large concentrations of peat, gravel, and sand. These poorly drained areas shelter and wet and mesic prairie communities, supporting populations of aspen and other fast-growing trees between prairie fires. The aspen parkland once covered vast acreages within the poorly drained flatlands left by Glacial Lake Agassiz. Remnants existing today are a mosaic of wet prairie, sedge meadow, shrub thicket, and aspen groves.

References

Audubon Society. 1979. Field Guide to North American Wildflowers/Eastern Region. Alfred A. Knopf. New York.

Barr, Claude. 1983. Jewels of the Plains: Wildflowers of the Great Plains, Grasslands and Hills. University of Minnesota Press. Minneapolis, MN.